The invention is particularly applicable to the combination of a folding flap cylinder, having folding flaps or grippers, with a delivery system having delivery chains likewise supplied with grippers.
British Patent No. 747,444 describes a folding apparatus in which the folded substrates are received from the folding flap cylinder by a transfer cylinder which has grippers, for supply to a belt system which operates at a lower speed than the circumferential speed of the transfer cylinder. The circumferential speed of the transfer cylinder is above the speed of the receiving belt system, and is reduced with respect to the surface speed of the folding flap cylinder by about 35%. The folded products are thus transferred from the folding flap cylinder and the transfer cylinder under conditions in which the speed of the transfer cylinder is substantially different from the surface speed of the folding flap cylinder. This results in compression and crushing of the sheets at the ends from time to time. Damage to the sheets at those end portions which are to be gripped by the grippers is unavoidable. When the folded products are transferred to the belts, they are transferred in irregular intervals thereon which interferes with smooth operation of subsequent units coupled to the delivery belts for further handling of the substrates.